Method and apparatus for use in manufacture of rubberized fabrics



Aug. 18, 1931. w BROWN 1,819,986

METHOD AND APPARATUS FOR USE IN MANUFACTURE OF RUBBERIZED FABRICS Filed June 8, 1922 rofn Producer- Gas Ouf/ef 120 y WBrr) I V!) Patented Aug. 18, 19 31 4 UNITED STATES PATENT OFFICE BOY W. BROWN, 01 AKRON, OHIO, ASSIGNOR TO THE FIRESTONE TIRE AND RUBBER COMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO METHOD AND APPARATUS FOR USE IN MANUFACTURE OF RUBBERIZED FABRICS Application filed June 8,

This invention relates, in a general way, to the manufacture of rubberized fabric particularly to fabric designed and intended to be used in the manufacture of articles of rubber and fabric, such as automobile tires, or

the like, in which the fabric is prepared by being passed through a bath of rubber in solution.

The usual solvent for rubber employed is 1. benzol, which, because of its highly inflammable character, requires specially constructed apparatus for the drying of the fabric and recovery of the benzol. In the form of a paratus to which this invention relates, is the Fabric is led through a bath of rubber in solution and then into a large enclosed chamber which is heated so that the benzol will evaporate quickly. In order to prevent explosions occurring in the interior of the dr 20 mg chamber, the atmosphere therein usual y contains an inert gas, such as carbon dioxide or producer gas, in such proportion as to constitute a non-inflammable mixture with the benzol. It is essential that the percent- 25 age of producer gas relative to the benzol be maintained at a definite amount in order to make the operation of the apparatus safe and practicable, and as the apparatus is necessarily closed during operation, it is essential 80 that some means be provided for readily determining the character of the gaseous contents of the drying chamber.

The purpose of this invention is to devise a sim 1e and efiicient device for indicating 35 the re ative percentage of benzol and producer gas in the drying chamber and to so construct the various parts of the apparatus that the readings obtained thereby will be accurate.

For this purpose there is combined with the drying chamber a device by which the con-. tents of the chamber may be determined at all times, and by which, should the percentage of benzol be increased, it will be 45 immediately indicated. In this manner the 1922. Serial No. 566,892.

operation of the drying apparatus will be safe at all times.

In the drawings accom anying the application is shown one form of the device in combination with any suitable drying apparatus, it being understood that, havin explained the principles of the invention, 0 anges and modifications may be made without sacrificing the essentials of the invention.

n the drawings:

Figure 1 is a view showin diagrammatically, the arrangement of t e various elements which constitute the apparatus of the invention;

Figure 2 is a cross section through one form of resistance member which constitutes one element of the invention; and

I'Iigure 3 is a plan view of the resistance C01 There is here shown at 1, a form of drying chamber and while any suitable type of enclosed chamber may be used, the one lllLlS- trated has been in successful operation and may be described briefly. The fabric is indicated b the numeral 2 passing from a supply ro-l 3 into a tank 4 in which is located the bath of rubber dissolved in benzol, or other solvent.

The fabric passes into the rubber solution and then through a passa eway 5, the walls of which dip into the rub er solution. In the passage 5 are located squeeze rolls 6 which force the rubber into the fabric and expel an excess of the solution. The fabric then enters the enclosed drying chamber 1 through a gateway 7 and while in the chamber is looped back and forth over idler rolls 8 and past a plurality of heaters 9 until it is dried sufficiently to be conducted from the chamber through a gateway 10 and is rolled up at 11.

The inert gas with which the chamber is filled is conducted into the chamber through an inlet pipe 12, and the chamber is emptied through a pipe 13 at the bottom of the chamber by which the inert gas and fumes of benzol or other solvent are led to an suitable reclaimin apparatus where the so vent is recovered or reuse.

In order to determine and indicate the ercentage of benzol in the mixture taken rom the drying apparatus, if benzol is used, so that the contents of the chamber may be maintained at a safe and workable stage, I make use of certain well known properties of gas by which they affect the electric resistance of conductors surrounded by the g From the producer gas line 12, there is provided a branch pipe 14 and from the drymg chamber outlet pipe a branch pipe 15, each pi e being of substantially t e same size. 'l he gas from each line is then led to a filter 16 and through a narrow orifice plate 17 so that both the producer gas and the chamber gas, as the gas from the drying apparatus may be called, are freed from any foreign substance and given a constant velocity with low pressure. From the orifice plate 17, the producer gas is conducted b a pipe 18 to and discharged within a chamber or box 19 which contains a coil of resistance wire. The chamber gas is led from plate 17 by pipe 20 to a second chamber or box 21 which also contains a resistance coil.

Que of these chambers or boxes is illustrated in Figures 2 and 3, in which the box is composed of two recessed plates 22 between which is held a disk of suitable nonconducting substance, preferably a sheet of mica 23, in the center of which is located an aperture 24. The resistance coil is indicated by the numeral 25 and is passed back and forth across the aperture. The gas enters the chamber on one side of the plate 23 and leaves at the other side so that it must pass across the coil.

The producer gas and the chamber gas pass out of the resistance coil enclosure by pipes 26 and discharge below the surface of water contained in a jar 27. By-passes 28 having control valves 29 may also lead from the pipes 18 and 20 to the water jar 27 so that the amount of gas passing over the coils 25 may be regulated.

The water in the jar is supplied by a pipe 30 and kept at a constant level by overflow ipe 31, having a trap 32 therein. An outet pipe 33 serves to withdraw the mixture of ases from the top of the water jar.

he coils 25 are located on either side of a Wheatstone bridge 34, the galvanometer of which is indicated by numeral 35. The Wheatstone bridge, containing the coils 25, is so arranged and adjusted that when the percentage of benzol in the chamber 1 is at a safe and workable point, the current flowing on both sides of the bridge will be the same and the galvanometer will not register.

Should the percentage of benzol increase,

the gas flowingaround the right coil 25 will i change in character and the resistance of the right-hand coil will vary, due to the chan in thermal conductivity of the gas, and t e change will be registered on the galvanometer. It is desirable that the current through the coils on both sides of the Wheatstone bridge maintain their temperature somewhat higher than the temperature of the gases which pass around them, so as to-obtain correct readings from the installation.

In order to obtain the accurate results desired, the gases flowing over both coils 24 should be freed from foreign substance, which is assured by the gas filters, and the velocity should be constant while the volume is low as will be assured by the orifice plates and the by-pass 28 and also by the water jar through which the gases are exhausted under the same conditions. Also, to obtain the best results, the temperature of both' coils should be constant and should be relatively high, this being assured by the heating coils 36 surrounding each resistance box 22.

The particular form of apparatus shown is such as has been found to operate satisfactorily and to give excellent results in determining the benzol content of the dr ing chamber, and while the description has een precise and detailed to enable one skilled in the art to practice the invention, it will be understood that changes and modifications may be made without varying the invention as comprised within the scope of the appended claims.

What I claim is:

1. An apparatus for the uses and purposes set forth comprising, the combination of an enclosed drying chamber adapted for the drying of material dissolved in a volatile solvent, means for admitting gas to one side of the chamber and exhaustin the as from the other side of said cham er, 0 a device arranged to be efiected'by the incomin and outgoing gases for comparing the re ative character of the said gases to determine the content of volatilized solvent in the outgoing I gases.

2. An apparatus for the uses and purposes set forth comprising, the combination of an enclosed chamber adapted for the drying of material dissolved in a volatile solvent, means for withdrawing the solvent from the chamber, a resistance coil, and means for conducting a portion of the gases from the chamber and passing it over said coil.

3. An apparatus for the uses and urposes set forth comprising, an enclose drying chamber, means for drying material containing a volatile solvent in the chamber, means for withdrawing gas from the chamber, a resistance coil, means adapted to conduct a portion of the withdrawn gas around the resistance coil, and means for measuring the resistance of said coil.

4. An apparatus for the uses and purposes set forth comprising, an enclosed chamber, means for drying material containing a volatile solvent in said chamber, means for supplying said chamber with an inert gas, means for withdrawing the gas from the chamber, two resistance coils, means for comparing the resistance of said coils, means for passing a portion of said inert gas over one of said coils, and means for passing a portion of said chamber gas over the other .coil.

5. An apparatus for the uses and purposes set forth comprising, an enclosed chamber, means for drying material containing a volatile solvent in the chamber, means for conducting a gas to the chamber, means for withdrawing the gaseous content from said chamber, by-passes from said conducting means and said withdrawing means, resistance members in said by-passes, and a device for measuring the relative resistance of said members.

6. An apparatus for determining the solvent content of a drying chamber comprising, an enclosed chamber, means for admitting an inert gas to one side of said chamber, means for withdrawing solvent carrying gas from the other side of said chamber, a branch pipe for said inert gas, a second branch pipe for 3 the chamber gas, means for controlling the velocity of ases in said pipes, a resistance coil in each ranch pipe, and an electrical resistance measuring device connected to said coils.

7. An apparatus for determining the solvent content of a drying chamber compris-' ing, an enclosed chamber, means for admitting an inert gas to one side of said chamber, means for withdrawing solvent carrying gas 40 from the other side of said chamber, a branch pipe for said inert gas, a second branch pipe for the chamber gas, means for controlling drying chamber.

' ROY W. BROWN.

. the velocity of gases in said pipes, a resistance coil in each branch pipe, an electrical resist- 45 ance measuring device connected to said coils, and means for controlling the temperature of the gases surrounding the resistance coils.

8. Apparatus of the class described, comprising a plurality of fluid conducting systems, each having a discharge outlet, said outlets being on a common level, and a device common to said systems for maintaining a constant head of a liquid above said outlets 55 and substantially enclosing said liquid.

9. A method adapted for use in the manufacture of rubberized fabric or the like, in which the material is impregnated with a rubber solution and is treated in a drying w chamber, said method comprising determining the character or composition of the gaseous content of said chamber by submitting V said gaseous content to a device responding to changes in the thermal conductivity of the gaseous content, comparing the variation in 

